How does pregnancy affect functional residual capacity in terms of apnea and the risk of hypoxia?

During pregnancy, functional residual capacity (FRC) is decreased primarily due to several physiological changes. As the uterus expands, it occupies more space in the abdomen which can elevate the diaphragm, effectively reducing lung volume and leading to a decrease in FRC. This reduction can influence the respiratory mechanics and gas exchange.

Lower FRC during pregnancy can contribute to a higher risk of hypoxia in certain situations, particularly during episodes of apnea, as there is less reserve volume of air in the lungs for effective gas exchange. In healthy pregnant women, it is essential to manage this risk, especially if they have underlying respiratory issues or are undergoing procedures that may exacerbate apnea.

The decrease in FRC highlights the need for careful monitoring of breathing patterns and oxygenation levels during childbirth and other peripartum events, as lower residual capacity may compromise oxygen delivery during periods of hypoventilation.